Reservoir System for Gas Delivery to a Patient

ABSTRACT

A breathing system is provided that employs a reservoir for holding oxygen or an oxygen and medicine mixture while the patient is not inhaling. The reservoir generally prevents waste and reduces cost and helps prevent the patient from re-inhaling the previously exhaled gases. The reservoir also may include a flange extending from an inlet thereof that allows the reservoir to be positioned in an inverted position.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation-In-Part of U.S. patent Ser. No.13/188,793, filed Jul. 22, 2011, which is a Continuation-In-Part of U.S.patent Ser. No. 12/688,295, filed Jan. 15, 2010, which claims thebenefit of U.S. Provisional Application Ser. No. 61/145,318, filed Jan.16, 2009, the entirety of each application being incorporated byreference herein.

FIELD OF THE INVENTION

Embodiments of the present invention generally relate to a breathingsystem designed to provide gas, such as an oxygen and medicine mixture,to a patient.

BACKGROUND OF THE INVENTION

Hospitalized patients with pulmonary or cardiovascular health issuesoften require supplemental oxygen. Typically, supplemental oxygen isdelivered to a patient from an oxygen source that is interconnected bytubing to a patient interface, e.g., a mouth piece or a mask. Inaddition, some patients require medicine, which is delivered to thepatient in the form of aerosolized particles mixed with the oxygen by anebulizer that is interconnected to the tubing and positioned betweenthe oxygen source and the patient interface. “Gas” as used herein shallrefer to the mixture of oxygen and medicine. Those of skill in the artwill appreciate that the source may deliver compressed air, a mixture ofhelium and oxygen, or any other substance that is typically used forpatient care.

One drawback of prior art breathing systems is that the patient oftenre-breathes exhaled gas which reduces the amount of medicine-rich gasthat would otherwise be received or drawn in by the patient. To avoidthis drawback, breathing systems often include an inlet check valve orsimilar device that prevents exhaled air from intermingling with theincoming or supplied gas. More specifically, the pressure of the exhaledgas is sufficient to close the inlet check valve so that exhaled gas isforced through vents or an outlet port located between the patient andthe inlet check valve. Pressure generated by the patient's inhalationopens the inlet check valve which allows the patient to breath in theprescribed gas.

It is another drawback that breathing systems of the prior art oftenwaste medicine. More specifically, the source of many breathing systemscontinuously output oxygen at a predetermined but variable mass flowrate and pressure. Thus, when the patient is not inhaling, i.e., duringexhalation or during the dwell period characterized as the time betweeninhalation and exhalation, gas continues to be delivered. As a result,the oversupplied gas is vented through the outlet port and/or throughmask vents. To account for this decrease in medicine delivery to thepatient, health care providers typically increase the amount of medicineadded to the incoming oxygen. In an extreme example, a healthcareprovider will prescribe three times the required dosage to accommodatelosses, which is wasteful and increases healthcare costs. One attempt tosolve the problem of waste has been to incorporate a reservoir bag intothe gas delivery system to capture the delivered gas when the patient isnot inhaling and subsequently deliver the captured gas to the patientupon the next breadth, which reduces the amount of gas vented toatmosphere. When the patient does inhale, the gas stored in thereservoir bag is inhaled along with gas that is being continuouslydelivered by the supply source.

Often reservoir bags are thick-walled and made of a durable material towithstand damage associated with shipping, handling, and use.Thick-walled construction, however, affects the ability of the bag toinflate and therefore adversely affects the ability of the bag tocapture excess gas. It follows that as the pressure required to inflatea thick-walled reservoir is greater than the pressure required to openthe inlet check valve, the pressurized gas delivered to the patientduring the dwell time will often flow to the mask only to be vented.Stated differently, the inlet check valve of many breathing systems mayopen without the reservoir bag being filled and the gas will vent toatmosphere through the outlet port or mask vents rather than filling thereservoir.

One ineffective response to this problem is to increase the pressure ofthe oxygen source, and thus the gas, to ensure the bag inflates.However, increasing the source pressure will amplify the wasteful effectif the reservoir bag does not inflate quickly. That is, the pressure ofthe system is directly proportional to the gas mass flow rate which inturn is directly proportional to gas losses through the outlet port whenthe inlet check valve inevitably opens. And, even if the higher pressuregas completely inflates the reservoir bag, eventually the pressure ofthe incoming gas will urge the inlet check valve open, which allows thegas to vent through the outlet port. As one of skill in the art willappreciate, losses will be greater than those experienced by a systemoperating at a lower pressure.

Another way to address the medicine waste issue is to vary the size ofthe opening of the outlet port. U.S. Pat. No. 5,613,489 (“the '489patent”), which is incorporated herein by reference, is directed to anoutlet port comprised of a selectively adjustable orifice that providesadjustable resistance to exhalation. As one of skill in the art willappreciate, the greater the resistance to exhalation, the greater thepressure within the housing, which keeps the inlet check valve closedwhen the patient exhales and during the dwell time. The adjustableorifice may also be used to control exhalation by producing a positiveexpiratory pressure (PEP) which enhances patient therapy. The orifice ofthe exhalation port described in the '489 is adjusted by altering awedge-shaped opening from about 10 degrees to about 60 degrees. Onedrawback with this method of controlling exhalation is that a path isalways open. Thus, if the system of the '489 patent is used with aself-inflating reservoir, as will be described in detail below, ambientair will be drawn in through the orifice when the patient inhales. Thatis, patients with poor lung function will not be able to provide enoughnegative pressure during inhalation to collapse a self-inflatingreservoir, which maximizes medicine delivery, without the orificeleaking ambient air.

Reservoir bags of the prior art are often not easy to clean and reuse.Thus many individuals choose to discard reservoir bags, which iswasteful and expensive. In addition, those individuals who decide toclean and reuse their reservoir bags often find it difficult to ensurethat all cleaning fluids are expelled from the reservoir bag.

Accordingly, there is a long standing and unresolved need to provide asystem for delivering medicine to a patient that efficiently stores areserve of gas when the patient is not inhaling, thereby eliminating orsubstantially reducing medicine waste by making the reserve available tothe patient when he or she subsequently inhales.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a gas delivery system witha reservoir wherein internal system pressure requirements areestablished that ensure that continuously produced and supplied gas iscaptured by filling or substantially filling a reservoir when thepatient is not inhaling. More specifically, one embodiment of thepresent invention employs an inlet check valve with increasedresistance. Further, resistance to opening the inlet check valve may beadded to the system, such as by placing a filter, a throttle—which mayor may not be variable, decreased diameter tubing, or some othermedically inert porous obstruction upstream of an outlet port, which islocated between the patient and the inlet check valve. As used herein,“upstream” refers to a position closer to the gas supply and away fromthe patient. Still further, the wall thickness of the inflatablereservoir may be reduced, which will facilitate inflation by reducingthe pressure needed to inflate the reservoir. Each of these solutions,alone or in combination, will capture the continuously-produced andsupplied gas such that a reserve is available for the patient, whichwill reduce waste. The resistance to gas flow occurs before the gasreaches the outlet port of the delivery system. In other words, anystructure or component added, altered, or selectively altered forpurposes of increasing the internal resistance to gas flow toward theoutlet port must not be positioned between a patient interface, i.e., amouth piece or mask, and the outlet port, otherwise the solution will beineffective as the gas will vent to atmosphere through the outlet port.

Additionally, the internal system pressure may be adjustable relative tothe volume and rate of the patient's breath cycle such that the internalsystem pressure may be set to cause the reservoir to fill or issubstantially fill before each inhalation cycle.

It is another aspect of some embodiments of the present invention toprovide self-inflating reservoir. More specifically, reservoirs made ofa resilient material, such as a shape-memory polymer, are employed thatreturn to their original shape after compression caused by inhalation.The material used by one embodiment is flexible polyvinyl chloride (PVC)or other similar elastomeric materials, such as silicon or styrenicblock copolymer (SBC) manufactured by Kraton Performance Polymers Inc.Further, as previously noted, the wall thickness of the contemplatedreservoir may be directly proportional to the pressure required toinflate the reservoir. Effective wall thickness is a function of thematerial selected and may range from about 0.100 mm near the opening ofthe reservoir to about 0.030 mm in some areas of the primary gas-holdingportion. In one embodiment, the wall thickness is consistent from theopening to about the midway point of a spherical reservoir (a firsthemi-spherical portion) wherein the remainder of the spherical reservoirfrom the midway point to the end of the reservoir (the opposedhemispherical portion) is made of a thinner or different material. Bydefining the reservoir material of manufacture and/or wall thickness,the amount of negative pressure created by the reservoir as it reboundscan be predetermined. Furthermore, the negative pressure assists infilling the reservoir and assists in keeping the inlet check valveclosed during patient exhalation and dwell time.

It is also noted that patients frequently do not breathe as deeply asthey should following many medical procedures. To resolve this, doctorswill prescribe the use of incentive spirometer which gives the patientand doctor a visual indication that they are breathing deeply. Theshape-memory reservoir of some embodiments of the invention will alsoprovide such visual feedback to the patient and the patient's doctor orattendant.

More specifically, it is yet another aspect of the present invention toprovide a somewhat stiff but resilient reservoir that will resistinhalation, which is a helpful therapy tool. More specifically,inhalation of gas from a reservoir of a contemplated embodiment of thepresent invention will take more patient effort. Increased efforttranslates into a deeper breath that will force medication deeper intothe patient's lungs. Forcing the patient to breathe deeper has the addedbenefit of preventing pneumonia as deep breaths necessarily help preventfluid build-up in the patient's lungs. Further, by monitoring the degreeof inhalation by the patient through observation of the shape of thereservoir during patient inhalation and exhalation (e.g., the reservoirexpanding on exhalation and collapsing or contracting to a degree duringinhalation), the drug administration process may be similarly monitored,and as such the reservoir provides biofeedback to the patient and/or thepatient's attendant regarding the patient's breathing pattern.

It is another aspect of the present invention to provide a reservoirthat collapses in a controlled fashion to ensure that the gas containedin the reservoir is completely expelled. Bag reservoirs of the prior artcan collapse in such a way to block the reservoir opening and therebytrap some gas inside the reservoir. Thus, reservoirs of some embodimentsof the present invention employ thicker and stiffer walls adjacent tothe open end than the gas-holding portion of the reservoir to preventthe collapsing reservoir from blocking the open end and trapping gas.Other reservoirs employ stiffening ribs or seams that help controlreservoir collapse to prevent blocking the opening. Still otherreservoirs of the contemplated invention are made of a combination ofmaterials that collapse in a predetermined manner. For example, in oneembodiment the reservoir is made of two distinct materials, one stiffand less apt to collapse than the other. In operation, the more flexiblematerial, which is located away from the reservoir opening, willcollapse first. Any of these reservoir configurations and those similarthereto has the advantage of maintaining the opening while having theprimary gas-holding portion fully collapse upon inhalation, which allowssubstantially all of the stored gas to be inhaled. Alternatively, thereservoir opening may be held open with an adapter that is inserted intothe opening.

It is a related aspect of the present invention that condensation, whichcontains medicine, in the reservoir is reduced. More specifically,collapsed walls of prior art reservoir bags may stick together and trapgas within folds, creases, or pockets which leaves medication adhered tothe inside surface of the bag. A test of one embodiment of the presentinvention reduced the amount of condensation in the reservoir by 90%.

It is yet another aspect of the present invention to provide a breathingsystem, comprising: a gas source; a housing having: a first inlet influid communication with said gas source, a first port in fluidcommunication with a patient interface, and a second port in fluidcommunication with a reservoir; an outlet, wherein said housing includesa first check valve positioned between said first inlet and said outlet;and wherein output from said gas source flows to said first inlet and tosaid reservoir, the output inflating said reservoir until said firstcheck valve is opened, which allows the output to be directed from saidreservoir and said gas source to said patient interface.

It is another aspect of the present invention to provide a method ofreducing waste in the delivery of aerosolized medicine or gas to apatient comprising: providing a gas source; providing a housing having:a first port associated with said gas source, a second port associatedwith a reservoir, a third port associated with a patient interface, anda fourth port, and a check valve positioned between said first port andsaid fourth port;

delivering a gas from said gas source to said first port of saidhousing; directing said gas to said reservoir via said second port;opening said check valve upon patient inhalation; directing said gasfrom said reservoir to said patient interface; closing said check valvewhen the patient is not inhaling; and directing exhaled air out of saidhousing through said fourth port.

It is yet another aspect of embodiments the present invention to providea reservoir bag that includes a flange extending from its inlet. Theflange is used to support the reservoir in an inverted position so thatwater can exit therefrom which facilitates drying. As some of thereservoir bags contemplated herein are made of soft blow-moldedmaterial, stiffening members may be included that help prevent reservoircollapse when inverted. The stiffening members, e.g., ribs, may beintegrated into the body of the reservoir bag. For example, the toolsused to form the reservoir bag made create thickened areas that act asstiffening members.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of one embodiment of a currently availablecommercial gas delivery system, including a nebulizer.

FIG. 2 is an exploded view of a first embodiment of the presentinvention, including a nebulizer.

FIG. 3 is a housing employed by some embodiments of the presentinvention.

FIG. 4 is an exploded view of an alternative embodiment of the presentinvention, without a nebulizer.

FIG. 5 is an exploded view of a housing employed by another embodimentof the present invention;

FIG. 6 is an exploded view of a breathing system that employs thehousing of FIG. 5;

FIG. 7 is an elevation view of a self-inflating reservoir of oneembodiment of the present invention;

FIG. 8 is an elevation view of FIG. 7 shown in a collapsed state;

FIG. 9 is a perspective view of the breathing system of FIG. 6 showing apatient inhaling through a mouth piece;

FIG. 10 is a perspective view of the breathing system of FIG. 8 showinga patient exhaling

FIG. 11 is a front elevation view of the reservoir of another embodimentof the present invention; and FIG. 12 is a cross-sectional view of FIG.11.

While the following disclosure describes the invention in connectionwith those embodiments presented, one should understand that theinvention is not strictly limited to these embodiments. Furthermore, oneshould understand that the drawings are not necessarily to scale andthat in certain instances, the disclosure may not include details thatare not necessary for an understanding of the present invention, such asconventional details of fabrication and assembly.

DETAILED DESCRIPTION

FIG. 1 is an example of a current commercial aerosol delivery system 10that does not employ a reservoir bag or one-way valving system. Oxygenflows though supply tubing 12 to the nebulizer 14 that adds medicine tothe oxygen to create a gas comprised of aerosolized gas. The gas travelsthrough housing 16 and mouth piece 18 toward the patient, into a tube 20or both, depending upon the dynamic internal system pressures. The mouthpiece 18 may be replaced by a mask 14 as shown in FIG. 4. The tube 20may act as a reservoir wherein inhalation will draw gas from the tube20, through the housing 16 and to the mouth piece 18 as well as from thenebulizer 14. Upon exhalation, the exhaled gases flow out through themouth piece 18 and housing 16 into the tube 20 and ultimately intoatmosphere through outlet port 22 of the tube 20. During any period oftime when the patient is not inhaling, the aerosol mixture from thenebulizer 14 will flow toward the mouth piece 18 and toward the outletport 22. The portion of the gas that flows toward the outlet port 22will purge at least some of the exhaled CO₂ that may reside in the tube20. However, if adequate flow sufficient to achieve a complete purge ofCO₂ from the tube 20 is not provided, the patient may re-breathe the CO₂residing in the tube 20 upon subsequent inhalation. In addition, usingincoming gas to purge exhalation gases wastes medication and reduces theprescribed volume of medication that is intended for the patient,thereby requiring the dosage to be increased due to system waste.

Turning to FIGS. 2 and 3, a pulmonary drug delivery system 30 is shown.In general terms, the pulmonary drug delivery system 30 comprises ahousing 32 having a patient interface port 33, which may be customizedto be the interface with a patient via a mouth piece 34 or a mask. Thehousing 32 also possesses a reservoir port 36 and a nebulizer port 39associated with the main housing 32. A nebulizer 38 is associated withthe nebulizer port 39 and an oxygen source 40 by way of tubing 42.Further, an inflatable/deflatable reservoir 44 associated with the mainhousing at the reservoir port 36. The oxygen source 40 may be aself-contained oxygen tank, a hospital's own oxygen source, including anoxygen generating device, a source of ambient air, a blender or manifoldthat is connected to a combination of sources, an oxygen concentrator,and a compressor, for example. A connector 46 may be used tointerconnect the reservoir 44 to the main housing 32, and a band 48 ortape provides one option of sealing the reservoir 44 to the connector46. An oxygen line 42 is attached between the nebulizer 38 and theoxygen source 40. The nebulizer receives a continuous supply of oxygenfrom the source 40 and mixes the oxygen with aerosolizes medicine toform a gas for inhalation by the patient. An inlet check valve 50 isinstalled in the main housing 32 that opens upon inhalation, therebyallowing gas to be drawn in by the patient by the mouth piece 34. Thevalve 50 also prevents exhaled gas from flowing to the inflatablereservoir 44. A seat (see FIG. 3, #51) may be formed in the housing 32upon which the valve 50 is positioned.

The flow rate at which oxygen is supplied to the nebulizer is a knownamount and may be adjusted as required. In one embodiment, the pressurebeing delivered by the source is greater than the pressure required toopen the inlet check valve 50, but the flow rate of the pressurizedoxygen is decreased so that it takes some time for the pressure in thereservoir 44 and housing 32 to reach a level that would open the inletcheck valve 50. Accordingly, when a patient is not inhaling, the gasexiting nebulizer 38 will accumulate in the reservoir. At some point,however, the inlet check valve 50 will open due to the pressure build upin the housing 32 and the reservoir 44, if the valve is not otherwiseopened by the patient's inhalation. Upon inhalation, the valve will openor remain open and allow the patient to receive the gas from thenebulizer 38, as well as the supply of gas contained in the reservoir44. If the patient is not inhaling at this time, the excess gas willvent through port 52 and PEP valve 53.

The flow rate of the gas from the nebulizer 38 should be adjusted tocorrespond with the patient's inhalation such that the volume of gasthat accumulates in the reservoir matches or nearly matches thepatient's inhalation volume intake, accounting for the volume of gasthat would also be simultaneously supplied from the nebulizer. Shouldthe patient over-breathe and deplete the volume of gas in the reservoir,the patient may still inhale the gas being generated by the nebulizer aswell as ambient air drawn through an outlet 52 or Positive ExpiratoryPressure (PEP) valve 53. When the patient exhales the inlet check valve50 will close and all exhaled gas will exit through the outlet 52 or thePEP valve 53. One of skill in the art will appreciate that the exhaledgas also may exit though another outlet integrated into the housing 32,the mouth piece 34, the mask (if applicable), etc. That is, the PEPvalve 53 is not necessarily required for the contemplated invention tofunction. The PEP valve 53 may employ a member 56 that is selectivelyadjusted to control the flow of fluid therethrough. In one embodimentthe PEP valve 53 is used in conjunction with a filter mechanism 54 tofilter exhaled gases, remove contaminants, bacteria, viruses and othercontaminates for the safety of healthcare workers and others attendingto the needs of the patient. During exhalation and any pause before thenext inhalation, the gas will inflate the reservoir 44. To ensure gas isnot wasted when the patient is not inhaling and to ensure the reservoir44 fills, even in the case of patients requiring high oxygen flow rates,which generate higher internal pressures that could cause the inletcheck valve 50 to open at times other then when the patient is inhaling,the resistance of the inlet check valve 50 may be increased. In oneembodiment, a manually adjustable spring is used to alter the resistanceof the valve 50. Alternatively, a second check valve of increasedresistance (not shown) may be placed in the delivery system upstreambetween the PEP valve 53 and inlet check valve 50. This second valvewould compensate for situations where the inlet check valve 50 wouldotherwise open at times other than during patient inhalation. Further,and by way of example, resistance could take the form of one or morefilters, some type of inert or non-harmful but porous obstruction, athrottle in the tubing, a throttle in the housing 32, a circuitous airpath, a flow path comprising flexible walls that expand and contractwith pressure changes, tubing with integrated pressure reliefcharacteristics (i.e., a hole covered by a flexible member that allowsgas to escape when the pressure of the gas reaches a predeterminedlevel), or a combination of one or more of these options. An importantfeature is that the internal resistance to gas flow toward the mouthpiece upstream of the PEP valve 53 is greater than that required to fillthe reservoir bag 44.

Referring now to FIG. 3, the housing 32 of one embodiment of the presentinvention is shown that includes a patient interface port 33, anebulizer port 39 and a reservoir port 36. The housing 32 also includesthe outlet 52 that is adapted to interconnect with the PEP device. Thevalve 50 is integrated into the housing 32 via an opening 55 in aportion of the housing 32. A cap 57 is also integrated to the opening toseal the housing 32. The valve 50 rests against a valve seat 51, whichmay be angled (α). The valve seat 51 will alter the pressure required toopen the valve 50 as a function of angle (α). More specifically, if thevalve is positioned vertically as shown, it will require less pressureto open if it is angled, for example, about 30 degrees, wherein theweight of the valve 50 must be additionally overcome to open the same.

FIG. 4 illustrates a non re-breather mask system incorporating anembodiment of the present invention. A patient mask 60 may have one ormore outlet check valves 62 that prevents ambient air from entering.Alternatively, the mask 60 may have exit vents that are not valves orthe exhalation may simply escape around the peripheral edges of themask. A housing 64 also includes an inlet check valve 66 installed toprevent exhaled gas from entering a reservoir bag 68. As describedabove, the force needed to open the inlet check valve 66 may beincreased to facilitate filling of the reservoir bag 68. The reservoirbag 68 may be attached to the housing 64 with an attaching device 70such as a band tie or tape. The housing 64 also is interconnected to anoxygen line 72 that is also associated with an oxygen or ambient airsource 74.

When the oxygen source is turned on, pressurized oxygen will fill thereservoir bag 68 until the patient inhales. On inhalation, the valve 66opens and valve(s) 62 close causing all of the inhaled gases to comefrom the oxygen supply 74 and/or the reservoir 68. The flow of oxygenmay be adjusted to meet the patient's requirements. On exhalation, valve66 closes and valve(s) 62 open to allow the exhaled gas to escape fromthe mask and the reservoir bag 68 to refill with oxygen. A nebulizer(not shown) may be added between the housing 64 and the oxygen supplyline 72 and the system will work in the same way but the reservoir andpatient will be provided with an aerosolized mixture of oxygen andmedicine or ambient air and medicine.

With the current state of the art non-re-breather mask systems, thereservoir bag is stiff, as described above, and in order to fill thereservoir bag when the patient is not inhaling the pressure from theoxygen supply must be sufficiently large. However, the increasedpressure also causes outlet valves 62 and 66 to open causing at leastsome of the oxygen or aerosol mixture to exit out to atmosphere when thepatient is not inhaling. Oxygen or aerosol mixture is thus wasted andthe quantity of medicine or oxygen must be increased to accommodate theloss and to ensure the patient receives the prescribed amount ofmedicine.

In one embodiment of the present invention the pressure required to openvalve 66 is adjusted to require a pressure greater than the pressurerequired to substantially fill the reservoir 68 but is less than thepressure needed to open the valve 66 when the patient inhales. Thisassures the patient receives the prescribed oxygen level, requires lessoxygen flow to achieve the prescribed oxygen levels and reduces oreliminates the loss of oxygen or the aerosol mixture. The system of FIG.4 may also utilize the methods for adjusting system pressures describedabove in connection with FIG. 2. Some embodiments of the presentinvention employ a semi-rigid, i.e., flexible reservoir. For example,the reservoir may be comprised at least partially of a material thatreacts to a negative pressure associated with inhalation but maintains apredetermined shape when not exposed to a pressure variation. This“memory-shape” or “self-inflating” reservoir will thus return to itsstatic or original shape in the absence of external or internalpressure, similar to the bulb of an eyedropper, an aspirator, etc. Thematerial of manufacture of the contemplated reservoir is any number ofshape-memory or flexible plastics, for example, flexible PVC of arelatively thin wall thickness in the range of 0.005-0.015 mm. As one ofskill in the art will appreciate the contemplated wall thickness wouldrequire adjustment depending on the material used. That is, the thickerthe material the more memory the part would possess but the less likelyit would collapse during inhalation. In addition, if the wall thicknessis too thin it would not have enough rigidity to be self inflating. Oneof skill in the art will appreciate that the reservoir can besubstantially rigid but includes a flexible portion that allowsexpansion or contraction of the flexible portion in response to patientbreathing.

The contemplated reservoir would facilitate cleaning or sanitationthereof as it will substantially maintain its shape when disconnectedfrom the system as the opening associated therewith may be oriented toallow drainage of cleaning fluid. This aspect has an advantage over asubstantially collapsible, less rigid bag that would prevent the escapeof moisture, thereby promoting bacteria and or mold growth which reducesthe life expectancy thereof

FIGS. 5 and 6 shows a housing of another embodiment of the presentinvention that is similar to that described above with respect to FIG.3. This embodiment of the present invention also includes a valve 94associated with the opening 55 that allows ambient air to be drawn in bya patient who requires an air volume that cannot be met by the suppliedgas or that stored in the reservoir. The valve 94 may be an umbrella, adiaphragm, or a butterfly valve. In operation, if inhalation is greaterthan the volume of the reservoir (not shown) and greater than the amountof gas being delivered through the nebulizer port 39, the valve 94 willopen. The valve 94 may include a plurality of holes (see #95, FIG. 9),which may be adjustable and which will dictate the negative pressureneeded to open the valve 94. If an umbrella valve is employed, thethickness of the valve dome 96, the material of manufacture, the valvepreload, along with the presence or absence of holes 95, will dictatethe negative pressure required for opening. By increasing the pressurerequired to open the valve 94, important resistance to inhalation isprovided. The housing thus forces the patient to draw in air fromoutside the system when the reservoir is depleted.

The housing of this embodiment of the present invention also includesoutlet PEP valve 53 associated with the outlet 52 similar to that shownand described in U.S. Pat. No. 5,613,489, which employs an orifice 97that may be selectively adjusted by rotating a member 56 to control theamount of exhaled air exiting the orifice 97. More specifically, byreducing the size of the orifice 97, the patient will have to exhalemore vigorously to accomplish a full and complete exhalation cycle. Theorifice 97 of this embodiment is associated with an outlet check valve98 that does not allow ambient air to “leak” into the system when thepatient inhales and adds little or no resistance to exhalation. Otherembodiments of the present invention omit the valve 94 and only employthe outlet check valve 98. The outlet check valve 98 may be a diaphragmor butterfly valve that is associated with a valve retainer 99interconnected to the outlet 52. Further, the valve 98 can be used inconjunction with an existing variable resistor, if needed.

Referring now particularly to FIGS. 6 and 7 a breathing system 30 thatemploys self inflating reservoir 100 is shown. The reservoir 100 returnsto its original shape when not exposed to a negative internal pressure.The wall thickness of the reservoir and the material of manufacturedictate how the reservoir will rebound. The reservoir 100 requires asufficient amount of inhalation pressure to collapse and expel thestored gas.

Once inhalation has ceased, the reservoir 100 will attempt to rebound toits normal state as the nebulizer refills the volume of the reservoir,thereby ensuring that a sufficient volume is provided to receiveincoming gas which will be taken in by the patient's next breath. Thereservoir 100 in one embodiment of the present invention has sphericalbody 102 and an inlet 106 that interconnects to the housing. Further,the reservoir 100 may have a ring 110 that is used to hang the reservoir100 in a downward facing orientation that facilitates drying.

FIG. 8 shows a reservoir 100 of one embodiment in a collapsed state.Here, one of skill in the art will appreciate that the area around thereservoir opening 106 remains unobstructed by the collapsed reservoir.This aspect of the present invention allows for a greater amount of gasto be expelled from the reservoir 100 when the patient inhales. FIG. 8also illustrates that the material composition of the reservoir may becustomized such that some portions are more flexible, i.e. collapsible,than others.

A typical inhalation/exhalation cycle is shown in FIGS. 9 and 10. Asshown in FIG. 9, gas 120 will be drawn into a housing 32 when thepatient 124 inhales. The negative pressure associated with inhalationwill open the inlet check valve 50 to allow gas from the reservoir 100to be taken in by the patient 124, which collapses the reservoir 100, aswell as from the supply 120. When the patient 124 exhales (FIG. 10), thevalve 50 will close and the exhaled gas will exit the housing throughthe orifice 97. During exhalation and the dwell period, gas will beprevented from reaching the patient by the inlet check valve 50 and thereservoir 100 will fill, which returns the reservoir 100 to its normalshape (assuming the internal system pressure is not greater than theinlet check valve 50 opening pressure). The resilient nature of thereservoir will also help return it to its normal state, which creates anegative pressure that keeps the valve 50 closed when the patient is notinhaling. When the patient inhales again the valve 50 will open and thegas will be initially drawn resistance-free from the reservoir 100 andfrom the oxygen supply line. Once the oxygen is sufficiently depletedfrom the reservoir 100, the reservoir 100 will start to collapse similarto that shown in FIG. 8. This resistance to inhalation in some cases isdesirable to help a patient take in medicine to a greater degree.

A test of one embodiment of the present invention was performed using anebulizer and a self-inflating, shape memory, reservoir. A respiratorypump was used to represent the inhalation and exhalation of a patientthat was able to provide 500 ml per breath, and inhalation to exhalationration of 1:1 at fifteen breaths per minute. A high efficiencyparticulate air (HEPA) filter, which represented the patient, was placedbetween the respiratory pump and the nebulizer. The HEPA filter,nebulizer, and the body of the self inflating reservoir were weighedprior to testing. Further, 3 ccs of sterile saline were placed in a bowlof the nebulizer and a nebulizer was weighed again. To commence thetest, the respiratory pump was switched on and the flow of nebulizer wasset to about 8 liters per minute. The system was allowed to functionuntil the nebulizer sputtered, which indicated that nearly all of thesterile saline (representing medicine) was completely administered. Allthe components were then weighed and the amount of weight loss of thenebulizer was compared to the weight gain of the other parts of thesystem. The self-inflating reservoir of some embodiments of the presentinvention gained less than 1% of weight, which is attributed to thenebulized solution, i.e., trapped medicine. For comparison, the systemsof the prior art that use a reservoir bag were tested. Such systemsyielded residual condensation in the bag (trapped medicine) greater than10% of the total fluid nebulized. By reducing the amount of condensationoccurring inside the reservoir, costs are reduced and the amount ofmedicine reaching the patient is idealized.

FIGS. 11 and 12 show a reservoir of another embodiment of the presentinvention. The reservoir 200 is comprised of a body 202 that isassociated with elongated member that ends at an inlet 206. Further, theinlet includes an extended flange 214 extending therefrom. In operation,the reservoir 200 is inverted and rests on the flange 214 to facilitatethe egress of water to 18 therefrom. As one of skill in the art willappreciate, the reservoir may be made out of a thin flow-molded materialthat may collapse under its own weight. Accordingly, some embodiments ofthe present invention includes stiffening members integrated into thebody 202 that sure that the reservoir remains generally expanded whiledrying.

The present invention, in various embodiments, includes components,methods, processes, systems and/or apparatus substantially as depictedand described herein, including various embodiments, sub combinations,and subsets thereof. Those of skill in the art will understand how tomake and use the present invention after understanding the presentdisclosure. The present invention, in various embodiments, includesproviding devices and processes in the absence of items not depictedand/or described herein or in various embodiments hereof, including inthe absence of such items as may have been used in previous devices orprocesses, e.g., for improving performance, achieving ease and\orreducing cost of implementation.

The foregoing discussion of the invention has been presented forpurposes of illustration and description. The foregoing is not intendedto limit the invention to the form or forms disclosed herein. In theforegoing Detailed Description for example, various features of theinvention are grouped together in one or more embodiments for thepurpose of streamlining the disclosure. The features of the embodimentsof the invention may be combined in alternate embodiments other thanthose discussed above. This method of disclosure is not to beinterpreted as reflecting an intention that the claimed inventionrequires more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Thus, the followingclaims are hereby incorporated into this Detailed Description, with eachclaim standing on its own as a separate preferred embodiment of theinvention.

Moreover, though the description of the invention has includeddescription of one or more embodiments and certain variations andmodifications, other variations, combinations, and modifications arewithin the scope of the invention, e.g., as may be within the skill andknowledge of those in the art, after understanding the presentdisclosure. It is intended to obtain rights which include alternativeembodiments to the extent permitted, including alternate,interchangeable and/or equivalent structures, functions, ranges or stepsto those claimed, whether or not such alternate, interchangeable and/orequivalent structures, functions, ranges or steps are disclosed herein,and without intending to publicly dedicate any patentable subjectmatter.

What is claimed is:
 1. A reservoir for a breathing system, comprising:body; a tube extending therefrom, said tube having a first endinterconnected to said body and a second end; and a flange extendingfrom said second end.
 2. The device of claim 1, wherein said reservoiris made of a blow-molded material.
 3. The device of claim 1, whereinsaid body includes a means for stiffening.
 4. The device of claim 3,wherein said means for stiffening are ribs integrated into said body. 5.The device of claim 1, wherein said body includes thickened areas thatfunction to stiffen said reservoir when it is inverted.